This invention relates to apparatus for collecting samples fluid in a storage pouch for subsequent transport to a laboratory for testing.
In the field of occupational health and environmental monitoring, it is desirable to collect samples of fluids periodically, and particularly environmental air for subsequent analysis. One of the procedures used is an inflatable bag or pressurized container which requires a pump to inflate or fill the device to an increased pressure. Another device involves the use of an evacuated sampling device to passively fill in response to release of the vacuum into the atmosphere. Such devices suffer from the problem of withdrawal of the sample which, in turn, creates a negative pressure in the container and limits the sample volume. Another method of atmospheric sampling is based upon simple displacement of the interior volume of the container in the atmosphere, for instance by removing water or other liquid from a container and allowing the atmospheric air to enter the container, drawn in by displacement of the liquid. This has the problem of simply organizing the arrangement but also there is the possibility that chemicals in the atmosphere may interact with the liquid.
Another approach is to provide a pouch made up of two layers of MYLAR (trade mark) heat sealed about their peripheries and containing between them a collapsed sponge. Upon piercing one of the layers with an injection needle to feed the sample into the pouch, the sponge tends to separate the layers of mylar and the sample fills the pouch. Once the sample is contained in the pouch, the pouch can be mailed or otherwise transported to a laboratory for subsequent analysis of the sample.
In all of the sampling techniques, including the use of a pouch, it is necessary to have a technician or some other trained person to place the sample in the container. This is an expensive procedure because it is often desirable to take samples on a periodic basis and this means that a technician must be present continuously although his actual work may occupy only a fraction of the technician's time.
Accordingly it is an object of the present invention to automate the collection of samples by prviding apparatus which will place samples periodically in pouches so that the apparatus can be left for a considerable length of time without it requiring a continuous monitoring by a trained technician.